JP2019018274A - Rotary tool - Google Patents

Abstract

To apply brake to a tip tool easily and surely even when a tip tool is a large sized tip tool.SOLUTION: A grinder 1 is configured so that, between an output shaft 12 and a spindle 35, a clutch mechanism 5A for connecting power to the spindle 35 side from the output shaft 12 by turn-on of a switch 9 in linkage with on/off of the switch 9, and interrupting power to the spindle 35 side from the output shaft 12 by turn-off of the switch 9, and a brake mechanism 5B provided closer to the spindle 35 side than to the clutch mechanism 5A, for braking the spindle 35 in power interruption by the clutch mechanism 5A, and releasing brake to the spindle 35 in power connection by the clutch mechanism 5A, are provided.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotary tool such as a grinder that rotates a tip tool.

  In a rotary tool such as a grinder that performs work by rotating a tip tool such as a disc-shaped grindstone, a brake mechanism is provided to stop inertial rotation of the tip tool at the end of the work in a short time. As exemplified in Patent Document 1, this brake mechanism normally brakes the output shaft by pressing a brake plate provided at the front portion of the output shaft of the motor with a brake shoe. By pressing the operation member such as a switch, the switch is turned on and the slider is moved forward in conjunction with the brake shoe to be released from the brake plate. When the pushing operation of the operation member is released, the switch is turned off and the slider is retracted, and the brake shoe is pressed against the brake plate to apply the brake.

JP 2006-209956 A

  However, in a large grinder having a particularly long overall length, a handle may be provided behind the motor housing, and a switch and an operation member may be provided on the handle. In this case, since the distance between the front brake mechanism and the rear operation member becomes long, it is difficult to provide a slider and interlock with the operation member. There is also a risk of failure. In addition, in a large grinder, the tip tool such as a disc-shaped grindstone becomes large in addition to the motor, so that a large inertia is generated and the brake mechanism generates a large amount of heat during braking, leading to a decrease in brake characteristics and component life. Although electric brakes can be used, there are cases where it is difficult to use electric brakes because of excessive load on the motor.

  Therefore, an object of the present invention is to provide a rotary tool that can easily and reliably brake a tip tool even if it is large.

In order to achieve the above object, the invention described in claim 1 is directed to a motor, a switch that controls ON / OFF operation of the output shaft of the motor by operating the operation member, and rotation of the output shaft. A rotating tool that rotates with the rotating shaft that rotates the tip tool,
When the switch is turned on, the power is connected from the output shaft to the rotating shaft between the output shaft and the rotating shaft. When the switch is turned off, the power from the output shaft to the rotating shaft is cut off. A clutch mechanism that is provided closer to the rotating shaft than the clutch mechanism, and brakes the rotating shaft when power is cut off by the clutch mechanism, and releases the braking of the rotating shaft when power is connected by the clutch mechanism; Are provided.
According to a second aspect of the present invention, in the configuration of the first aspect, the clutch mechanism is a centrifugal clutch that connects / disconnects power as the rotational speed of the output shaft increases / decreases.
According to a third aspect of the present invention, in the configuration of the second aspect, the centrifugal clutch is moved toward and away from the driven plate provided on the rotary shaft side in the axial direction as the rotational speed increases or decreases, and presses the driven plate. And a conversion member for connecting power.
According to a fourth aspect of the present invention, in the configuration of the third aspect, the surface of the driven plate opposite to the pressing side of the conversion member is a braking surface pressed by a brake member provided in the brake mechanism. To do.
According to a fifth aspect of the present invention, in the configuration of the second aspect, the clutch mechanism includes a moving body that moves in a radial direction in response to an increase in centrifugal force on the output shaft side, and an axial direction in accordance with the movement of the moving body. And a linkage member that moves and links with the brake mechanism to release braking of the rotating shaft.
According to a sixth aspect of the present invention, in the configuration of the fifth aspect, the centrifugal clutch is disposed outside in the radial direction of the output shaft, and the moving body and the linking member are disposed inside the centrifugal clutch in the radial direction. It is characterized by.
A seventh aspect of the invention is characterized in that, in the configuration of the fifth or sixth aspect, the moving body moves along a groove arranged in a spiral shape around the output shaft.
According to an eighth aspect of the present invention, in the configuration of the sixth or seventh aspect, a driven plate is provided on the rotating shaft side, and the inner peripheral surface of the outer cylindrical portion continuously provided on the radially outer side of the driven plate is a centrifugal clutch. The clutch surface to be connected / disconnected and the surface of the driven plate on the side opposite to the continuous side of the outer cylinder portion are brake surfaces pressed by a brake member provided in the brake mechanism.
According to a ninth aspect of the present invention, in the configuration of the fourth or eighth aspect, the brake mechanism penetrates the driven plate, contacts the conversion member or the linkage member of the clutch mechanism, and moves toward the driven plate side of the conversion member or the linkage member. A spacer member that separates the brake member from the driven plate according to the movement of the driven plate is provided.
According to a tenth aspect of the present invention, in the configuration of the first aspect, there is provided a solenoid that is in an OFF state when the switch is turned on and that is turned on when the switch is turned off. Connected and shuts off the power to the rotating shaft side when the solenoid is turned on, while the brake mechanism releases braking of the rotating shaft when the solenoid is turned off and brakes the rotating shaft when the solenoid is turned on. To do.
The invention according to claim 11 is the structure of claim 10, wherein a cam plate that rotates in conjunction with ON / OFF of the solenoid is provided, and a clutch operation plate provided in the clutch mechanism as the cam plate rotates, The clutch mechanism and the brake mechanism are operated by moving a brake operation plate provided in the brake mechanism in the axial direction.

According to the first aspect of the present invention, the clutch mechanism and the brake mechanism are provided between the output shaft on the motor side and the rotary shaft on the tip tool side, and the rotary shaft is braked by the brake mechanism. There is no need to provide an interlocking mechanism with the member, and when the switch is turned off, it is sufficient if braking is applied only to the rotating shaft side where power is cut off by the clutch mechanism. Therefore, the influence of heat generation and the risk of obstruction to the cooling flow path of the motor are reduced, and even the large rotary tool can brake the tip tool easily and reliably.
According to the second aspect of the present invention, in addition to the effect of the first aspect, the clutch mechanism is a centrifugal clutch, so that connection / cutoff of power to the rotary shaft side can be easily performed using rotation of the output shaft. Can be done.
According to the third aspect of the invention, in addition to the effect of the second aspect, the conversion member that presses the driven plate on the rotating shaft side is provided in the centrifugal clutch, so that the operation of the centrifugal clutch is driven by the conversion member. It can be efficiently transmitted to the board.
According to the fourth aspect of the present invention, in addition to the effect of the third aspect, the surface opposite to the pressing side of the conversion member in the driven plate is used as a braking surface. Therefore, one driven plate is used for connecting the clutch mechanism. It can also be used for braking of the brake mechanism and has a compact structure.
According to the fifth aspect of the present invention, in addition to the effect of the second aspect, the clutch mechanism includes the moving body and the linking member, so that the power connection by the clutch mechanism and the braking release of the rotating shaft by the brake mechanism can be performed. Can be executed at an appropriate timing.
According to the sixth aspect of the present invention, in addition to the effect of the fifth aspect, the centrifugal clutch is disposed on the radially outer side, and the moving body and the linking member are disposed on the radially inner side. Can be set separately from the timing of connecting / disconnecting and the timing of braking and releasing by the brake mechanism.
According to the seventh aspect of the present invention, in addition to the effect of the fifth or sixth aspect, the moving body is moved along the spirally arranged groove around the output shaft, so that the change in centrifugal force is achieved. Thus, the moving body can be quickly moved in correspondence with each other, and braking by the brake mechanism and release thereof are performed quickly.
According to the eighth aspect of the present invention, in addition to the effect of the sixth or seventh aspect, the inner peripheral surface of the outer cylindrical portion connected to the radially outer side of the driven plate is the clutch surface, and the outer cylindrical portion of the driven plate is Therefore, even if a centrifugal clutch that expands and contracts is provided, the driven plate can be used both for connecting the clutch mechanism and for braking the brake mechanism.
According to the ninth aspect of the present invention, in addition to the effect of the fourth or eighth aspect, the brake mechanism penetrates the driven plate and comes into contact with the conversion member or the linkage member of the clutch mechanism. By providing a spacer member that separates the brake member from the driven plate in accordance with the movement toward the driven plate, the connection of power to the driven plate, the release of braking, and the interruption and braking of power are always executed at appropriate timing. be able to.
According to the tenth aspect of the present invention, in addition to the effect of the first aspect, by employing the solenoid, the clutch mechanism and the brake mechanism can be quickly operated using the solenoid.
According to the eleventh aspect of the present invention, in addition to the effect of the tenth aspect, the clutch mechanism and the brake mechanism are operated by the cam plate that rotates in conjunction with the ON / OFF of the solenoid. Therefore, it becomes a rational configuration to operate both mechanisms.

It is a longitudinal cross-sectional view of the grinder of form 1. 2A and 2B are explanatory diagrams of a clutch / brake mechanism according to a first embodiment, in which FIG. 1A shows when the switch is OFF, and FIG. 2B shows when the switch is ON. It is explanatory drawing of the intermediate | middle housing of the form 1, (A) is an external appearance perspective view, (B) is a semi-sectional perspective view. It is a disassembled perspective view from the front of the clutch / brake mechanism of form 1. It is a disassembled perspective view from the back of the clutch / brake mechanism of form 1. FIG. 6 is an explanatory diagram of the clutch / brake mechanism of Embodiment 2, wherein (A) shows a cross section of the clutch mechanism portion, and (B) shows a vertical section (both when the switch is OFF). FIG. 6 is an explanatory diagram of the clutch / brake mechanism of Embodiment 2, where (A) shows a cross section of the clutch mechanism portion, and (B) shows a longitudinal section (both when the switch is ON). It is explanatory drawing of the clutch / brake mechanism of the form 2, (A) is a half cross-sectional perspective view, (B) is a cross-sectional perspective view of a clutch mechanism part. It is a disassembled perspective view from the front of the clutch / brake mechanism of form 2. It is a disassembled perspective view from the back of the clutch / brake mechanism of form 2. It is a longitudinal cross-sectional view of the grinder of the form 3. FIG. 6 is an explanatory diagram of a clutch / brake mechanism according to a third embodiment, in which (A) shows when the switch is ON and (B) shows when the switch is OFF. It is the sectional view on the AA line of FIG. It is a disassembled perspective view from the front of the clutch / brake mechanism of form 3. It is a disassembled perspective view from the back of the clutch / brake mechanism of form 3. It is the BB sectional drawing of FIG. It is a perspective view which shows operation | movement of a solenoid, (A) shows the time of solenoid OFF, (B) shows the time of solenoid ON, respectively.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Form 1]
FIG. 1 is a longitudinal sectional view of a grinder showing an example of a rotary tool. The grinder 1 includes a cylindrical motor housing 2 that accommodates a motor (commutator motor) 3 and extends in the front-rear direction, and a cylindrical intermediate housing 4 that is assembled in front of the motor housing 2 and accommodates a clutch / brake mechanism 5. A gear housing 6 that is assembled in front of the motor housing 2 and accommodates the output portion 7 and a handle housing 8 that is assembled in the rear portion of the motor housing 2 and accommodates the switch 9 and the like.
First, in the motor housing 2, the motor 3 includes a stator 10 and a rotor 11, and is accommodated in a posture in which the output shaft 12 of the rotor 11 faces forward, and the rear end of the output shaft 12 is within the motor housing 2. It is pivotally supported by a bearing 14 held by a bearing portion 13. As shown in FIG. 2, the front end of the output shaft 12 is coaxially and integrally fitted to the rear end of the drive shaft 30 in the intermediate housing 4, and together with the rear end of the drive shaft 30, the partition wall 15 in the intermediate housing 4. The shaft is supported by a bearing 16 held on the shaft. A centrifugal fan 17 is provided on the output shaft 12 behind the partition wall 15, and a baffle plate 18 is held between the motor housing 2 and the intermediate housing 4 behind the output fan 12.

In the intermediate housing 4, as shown in FIG. 3, the inner cylinder 20 is concentrically provided by radial ribs 21, 21,..., And the partition wall 15 closes the rear end in the inner cylinder 20. ing. Between the ribs 21, 21 outside the inner cylinder 20, there are air passages 22, 22... Penetrating in the front-rear direction to communicate the centrifugal fan 17 side and the gear housing 6 side.
Further, in the front of the inner cylinder 20, a cup 23 in which the rear part has a cylindrical shape with the same diameter as the inner cylinder 20, the front part is formed in a tapered shape, and a cylindrical folded part 24 is formed coaxially in the center. Are fixed to the rib 21 of the intermediate housing 4 with screws 26, 26,... From the front. In the assembled state of the intermediate housing 4 and the gear housing 6, the circular portion 27 provided on the rear surface of the gear housing 6 is coaxially fitted to the folded portion 24 of the cup 23.

A driven shaft 31 is provided in front of the drive shaft 30 coupled to the output shaft 12 in the intermediate housing 4. The front end of the drive shaft 30 is coaxially and separately rotatably supported at the rear end of the driven shaft 31 via a needle bearing 32 held at the rear end of the driven shaft 31.
The driven shaft 31 passes through the folded portion 24 of the cup 23 and the circular portion 27 of the gear housing 6, is supported by a bearing 33 held by the circular portion 27, and protrudes into the gear housing 6. A bevel gear 34 is integrally provided at the front end of the driven shaft 31. The clutch / brake mechanism 5 is provided between the driven shaft 30 and the drive shaft 31, and details will be described later.

  In the gear housing 6, a spindle 35 as a rotating shaft is provided in the vertical direction, and a bevel gear 36 provided at an intermediate portion of the spindle 35 is engaged with the bevel gear 34 of the driven shaft 31. The spindle 35 is pivotally supported by an upper bearing 37 held in the gear housing 6 and a lower bearing 39 held by a retainer 38 coupled to the lower side of the gear housing 6, and the lower end of the spindle 35 is retained by the retainer 38. It protrudes downward from. A disc-shaped grindstone 42 as a tip tool is detachably attached to the lower end of the spindle 35 by an inner flange 40 and an outer flange 41. 43 is a wheel cover that is attached to the retainer 38 and covers the rear half of the disc-shaped grindstone 42, and 44, 44,... Are exhaust ports that communicate with the air passage 22 of the intermediate housing 4 and open to the front surface.

  On the other hand, the handle housing 8 is composed of a pair of half housings that are assembled from the left and right with a small diameter portion 45 provided at the rear end of the motor housing 2, and a handle portion 46 extending rearward is formed at the rear end. . A switch 9 with a controller in which a plunger 47 protrudes downward is provided in the handle portion 46, and an operating member whose front end can swing up and down around the rear end is provided below the handle portion 46. A switch lever 48 is provided and is biased to a downward swing position by a coil spring 49. Here, when the switch lever 48 is pushed upward with a hand that grasps the handle portion 46, the plunger 47 is pushed in and the switch 9 is turned on. When the push of the switch lever 48 is released, the plunger 47 protrudes and the switch 9 is turned off. To do. At the front end of the switch lever 48, a lock-off lever 50 that engages with the handle housing 8 and restricts the pushing of the switch lever 48 is provided. A power cord 51 is connected to the rear end of the handle portion 46, and a plurality of intake ports 52, 52... Are formed on the left and right sides of the handle housing 8 in front of the handle portion 46.

2 and 3, the clutch / brake mechanism 5 includes a clutch mechanism 5A provided on the drive shaft 30 side and a brake mechanism 5B provided on the driven shaft 31 side.
First, as shown in FIGS. 4 and 5, the clutch mechanism 5 </ b> A includes a disk-shaped conversion plate 55 as a conversion member that is externally mounted on the drive shaft 30. The conversion plate 55 is spline-coupled to a spline portion 56 provided on the drive shaft 30 so that it can rotate integrally with the drive shaft 30 and can move back and forth. A flange 57 located on the front side of the partition wall 15 is integrally formed on the drive shaft 30 behind the conversion plate 55.
A clutch shoe 58 is fixed to the front surface of the conversion plate 55, and a circular holder portion 59 having a diameter slightly larger than that of the flange 57 is formed on the rear surface, and the four clutch grooves 61, .. And a centrifugal clutch 60 comprising clutch pins 62, 62,... Held in the respective clutch grooves 61 are provided.

The clutch groove 61 is arranged on each side of a square centering on the axis of the conversion plate 55 coupled to the spline part 56, and the inner peripheral side near the axis is the deepest part larger than the diameter of the clutch pin 62. The outer peripheral side has an inclined surface 64 that gradually becomes shallower toward the outer periphery. Therefore, the clutch pin 62 does not protrude from the rear surface of the holder portion 59 in the deepest portion 63, and partially protrudes from the rear surface of the holder portion 59 by the inclined surface 64 when the clutch pin 62 rolls to the outer peripheral side. Become. However, since the flange 57 of the drive shaft 30 is formed in such a size that the outer periphery is located on the outer edge of each clutch groove 61, the flange 57 prevents the clutch pin 62 from escaping from the clutch groove 61. Therefore, when the clutch pin 62 rolls in the radial direction of the conversion plate 55 from the deepest portion 63 along the front surface of the flange 57 and rides on the inclined surface 64, this radial movement pushes the conversion plate 55 forward. Converted to pressure, the conversion plate 55 moves forward.
The driven shaft 31 is coaxially provided with a circular driven plate 65 having a diameter slightly smaller than that of the conversion plate 55 at the rear end, and the driven plate 65 is formed with four through holes 66, 66,.

The brake mechanism 5B presses the brake plate 72 backward, a spacer ring 70 as a spacer member mounted on the driven shaft 31, a brake plate 72 as a brake member mounted on the spacer ring 70 via a bearing 71, and the like. And a coil spring 73.
First, the spacer ring 70 has a flange portion 74 for receiving the rear surface of the bearing 71 at the rear end, and four contact pins 75, 75,. However, it protrudes rearward through the through holes 66 provided in the driven plate 65 of the driven shaft 31. Thereby, the spacer ring 70 can rotate integrally with the driven shaft 31 and can move back and forth.

The brake plate 72 has a dish shape that is larger in diameter than the driven plate 65 and opens forward. On the outer peripheral surface, the front and rear ridges 76, 76... Are projected at equal intervals in the circumferential direction. 76 is fitted in concave grooves 77, 77... Provided in the same phase on the inner peripheral surface of the cup 23, and is held so as to be movable in the front-rear direction in a state in which rotation with respect to the cup 23 is restricted. Yes. Further, a brake shoe 78 is provided on the rear surface of the brake plate 72 and outside the contact pins 75, 75.
The coil spring 73 is externally mounted on the folded portion 24 in the cup 23, and the front end abuts on the inner surface of the cup 23 and the rear end abuts on the front surface of the brake plate 72, so that the brake plate 72 is attached together with the spacer ring 70 and the bearing 71. It is energized backward. Here, the protruding amount of the contact pin 75 from the rear surface of the brake shoe 78 to the rear is larger than the thickness of the driven plate 65 in the front-rear direction.

In the grinder 1 configured as described above, in the clutch / brake mechanism 5 in which the switch 9 is OFF, the brake plate 72 of the brake mechanism 5B is biased by the coil spring 73 as shown in FIGS. 1 and 2A. As a result, the brake shoe 78 is pressed to the retracted position (brake position) where it abuts against the front braking surface 65a of the driven plate 65 of the driven shaft 31. At this time, the spacer ring 70 is also retracted simultaneously, causing the contact pin 75 to protrude rearward of the driven plate 65 and contact the clutch shoe 58, thereby pressing the conversion plate 55 of the clutch mechanism 5A rearward. Therefore, the conversion plate 55 is urged to the retracted position (clutch release position) where each clutch pin 62 of the centrifugal clutch 60 is located at the deepest portion 63 of the clutch groove 61. In this state, the clutch shoe 58 of the conversion plate 55 is separated rearward from the clutch surface 65 b on the rear side of the driven plate 65 by the amount of protrusion of the contact pin 75 from the driven plate 65.
Therefore, the driven shaft 31 is braked when the brake shoe 78 of the brake plate 72 is pressed against the braking surface 65a of the driven plate 65, and the spindle 35 where the bevel gears 34 and 36 are engaged is also braked.

When the lock-off lever 50 is released and the switch lever 48 is pushed in to turn on the switch 9, the motor 3 is driven and the output shaft 12 rotates together with the rotor 11. Therefore, the drive shaft 30 integrated with the output shaft 12 and the conversion plate 55 coupled with the drive shaft 30 in the rotation direction also rotate (here, clockwise rotation toward the front).
Then, as shown in FIG. 2B, due to the centrifugal force generated in the centrifugal clutch 60, each clutch pin 62 rides on the inclined surface 64 from the deepest portion 63 of the clutch groove 61, and biases the coil spring 73 from the front. The conversion plate 55 is advanced against this. Since the forward stroke is set to be slightly longer than the protruding amount of the contact pin 75 from the driven plate 65, the conversion plate 55 has a forward position where the clutch shoe 58 presses the clutch surface 65b of the driven plate 65 ( Move to the clutch connection position. At the same time, since the spacer ring 70 is pushed back through the contact pin 75, the brake plate 72 is also advanced through the bearing 71, and the brake shoe 78 moves away from the braking surface 65 a of the driven plate 65 (brake release). Position).

Therefore, the driven shaft 31 that is connected to the conversion plate 55 and separated from the brake plate 72 rotates integrally with the drive shaft 30. Therefore, in the output unit 7, the spindle 35 rotates via the bevel gears 34 and 36, and the disc-shaped grindstone 42 is rotated. At this time, the spacer ring 70 also rotates together with the driven shaft 31, but the bearing 71 is interposed between the brake plate 72 and the rotation of the brake plate 72 is restricted by the protrusion 76 and the concave groove 77. Therefore, the brake plate 72 moves only forward.
On the other hand, when the centrifugal fan 17 rotates with the rotation of the output shaft 12, outside air is taken in from the intake ports 52, 52... And passes through the motor housing 2 to cool the motor 3. The cooled air passes through the centrifugal fan 17, enters the gear housing 6 through the air passage 20 of the intermediate housing 4, and is discharged from the exhaust ports 44, 44.

When the pushing operation of the switch lever 48 is released and the switch 9 is turned off, the energization to the motor 3 is stopped. At this time, the spindle 35 tries to rotate due to inertia. However, since the centrifugal force of the centrifugal clutch 60 is reduced by stopping the energization, the brake plate 72 and the spacer ring 70 are retracted by the bias of the coil spring 73, and the brake shoe 78 is driven. It returns to the retracted position (brake position) that contacts the plate 65. By the retraction of the spacer ring 70, the conversion plate 55 is retracted via the contact pin 75, and the conversion plate 55 is separated from the driven plate 65, and each clutch pin 62 is the deepest part of the clutch groove 61. Return to the reverse position (clutch release position) of FIG.
As a result, the driven shaft 31 is braked via the driven plate 65, so that the braking force is transmitted to the spindle 35 and the disk-shaped grindstone 42 is immediately stopped.

  As described above, according to the grinder 1 of the first aspect, the switch 9 is linked to the ON / OFF state between the output shaft 12 and the spindle 35. When the switch 9 is turned ON, power is supplied from the output shaft 12 to the spindle 35 side. The clutch mechanism 5A is connected and shuts off the power from the output shaft 12 to the spindle 35 side when the switch 9 is turned off. The clutch mechanism 5A is provided closer to the spindle 35 than the clutch mechanism 5A. And a brake mechanism 5B for releasing the brake of the spindle 35 when the power is connected by the clutch mechanism 5A, so that there is no need to provide an interlocking mechanism between the brake mechanism 5B and the switch lever 48. When the switch 9 is OFF, only the driven shaft 31 on the spindle 35 side where the power is cut off by the clutch mechanism 5A is applied. It is sufficient to multiply the braking by the brake mechanism 5B Te. Therefore, the influence of heat generation and the possibility of failure of the cooling flow path of the motor 3 are reduced, and even the large grinder 1 can brake the disc-shaped grindstone 42 easily and reliably.

Particularly, here, the clutch mechanism 5A is a centrifugal clutch 60 that connects / disconnects power as the rotational speed of the output shaft 12 increases / decreases. Can be easily performed.
In addition, the centrifugal clutch 60 moves toward and away from the driven plate 65 provided on the spindle 35 side in accordance with the increase and decrease of the rotation speed of the output shaft 12, and presses the driven plate 65 to connect the power. Since the conversion plate 55 is provided, the operation of the centrifugal clutch 60 can be efficiently transmitted to the driven plate 65 by the conversion plate 55.
Furthermore, since the surface opposite to the pressing side of the conversion plate 55 in the driven plate 65 is a braking surface 65a pressed against the brake plate 72 provided in the brake mechanism 5B, one driven plate 65 is connected to the clutch mechanism 5A. It can be used for both braking and braking of the brake mechanism 5B, resulting in a compact structure.

  In addition, the brake mechanism 5B penetrates the driven plate 65 and comes into contact with the conversion plate 55 of the clutch mechanism 5A. When the spindle 35 is braked, the conversion plate 55 is separated from the driven plate 65 and the conversion plate 55 is moved in the axial direction. Since the spacer ring 70 for separating the brake plate 72 from the driven plate 65 according to the movement is provided, the connection of the power to the driven plate 65 and the release of the braking, the interruption of the power and the braking are always executed at appropriate timing. be able to.

  In the first embodiment, the centrifugal clutch may be increased in number or the shape of the clutch pins. Moreover, it is good also as a ball shape instead of a pin shape. The shape of the conversion plate can also be changed as appropriate, and on the front surface that presses the driven plate, the clutch shoe may be omitted or a surface treatment (such as blasting or knurling) that increases frictional resistance may be performed. The same applies to the rear surface of the brake plate, and the brake shoe can be omitted or surface treatment can be performed. Conversely, it may be possible to provide shoes or surface treatment on the front and rear surfaces of the driven plate.

Next, another embodiment of the present invention will be described. However, since the structure other than the structure related to the clutch / brake mechanism is the same as that of the first embodiment, the same components are denoted by the same reference numerals, and redundant description is omitted, and only the clutch / brake mechanism will be described.
[Form 2]
In the grinder 1A shown in FIGS. 6 and 7, in the clutch / brake mechanism 5, the structures of the drive shaft 80 and the clutch mechanism 5A are different from those of the first embodiment.
First, as shown in FIGS. 8 to 10, the drive shaft 80 has three support pins 82, 82... Forwardly coupled to the front surface of the large-diameter flange 81 at equal intervals in the circumferential direction. A ring plate 83 having the same outer diameter as the flange 81 is connected to the front end of the support pin 82 in parallel with the flange 81. Further, the driven plate 65 of the driven shaft 30 is formed to have a larger diameter than the flange 81 and the ring plate 83, and an outer cylinder portion 84 positioned on the outer side in the radial direction of the flange 81 and the ring plate 83 is integrally formed on the outer periphery thereof. Is formed.

Further, between the flange 81 and the ring plate 83, as shown in FIGS. 9 and 10, the arc plate portion 86 that curves along the inner peripheral surface of the outer cylinder portion 84, and the front and rear sides inside the arc plate portion 86. Three clutch claws 85, 85... Each having a middle plate portion 87 projecting from the center of the direction to the center side are arranged and orthogonal to the middle plate portion 87 on the proximal end side in the circumferential direction of each clutch claw 85. The support pins 82 pass through the cylindrical portion 88 provided in each.
Therefore, each clutch pawl 85 is supported so as to be swingable between the flange 81 and the ring plate 83 around the support pin 82, and the front end side where the middle plate portion 87 is tapered can be projected and retracted in the radial direction of the flange 81. It becomes. However, since the middle plate portion 87 on the base end side of each clutch pawl 85 is provided with a stopper portion 89 projecting inwardly from the distal end side of the adjacent clutch pawl 85, each clutch pawl 85 has a distal end. The radial arc portion 86 on the side is in the radial direction between the outer position where it contacts the clutch surface 84 a that is the inner peripheral surface of the outer cylinder portion 84 and the inner position where the middle plate portion 87 on the front end side contacts the stopper portion 89. It can be infested. Tensile springs 90, 90,... Are stretched between a substantially central portion in the circumferential direction of the middle plate portion 87 of each clutch pawl 85 and a stopper portion 89 of the clutch pawl 85 adjacent on the tip side, Each clutch pawl 85 is urged to the inner position.

  Thus, between the flange 81 and the ring plate 83, the three clutch claws 85, 85,... Are connected to each other by the tension springs 90, 90,. As a result, the three clutch claws 85, 85,... Are expanded as a whole and pressed against the clutch surface 84a of the outer cylinder portion 84, and the three clutch claws 85, are contracted as a whole. Centrifugal clutch 60 </ b> A that can be expanded / contracted is formed between a contracted position where 85... Is separated from clutch surface 84 a of outer cylinder portion 84.

  Inside this centrifugal clutch 60A, a taper portion 91 tapering forward is projected on the front surface of the flange 81, and a plurality of clutches inclined at the same direction and at the same angle from the radial direction are projected on the front surface of the taper portion 91. Grooves 92, 92,... Are formed at equal intervals in the circumferential direction, and each clutch groove 92, as viewed from the front, moves toward the center as it goes in the rotational direction (the left rotational direction in FIG. 6A). It has a spiral shape that can be squeezed. Each of the clutch grooves 92 accommodates a steel ball 93 as a movable body so that it can roll. However, the center of each clutch groove 92 does not protrude from the surface of the tapered surface 91 because the steel ball 93 is immersed. It is formed in the deepest part 94, and is formed in the rolling surface 95 which goes to an outer peripheral side.

  Therefore, when the steel ball 93 rolls from the deepest portion 94 to the outer peripheral side, the steel ball 93 protrudes forward from the surface of the tapered portion 91 by the guidance of the rolling surface 95. The taper portion 91 is fitted with a linkage cap 96 as a linkage member having a front plate portion 97 through which the drive shaft 80 penetrates from the front, and the inner surface of the linkage cap 96 follows the inclination of the taper portion 91. An inner tapered surface 98 is formed to prevent each steel ball 93 from coming off from the clutch groove 92. Therefore, when each steel ball 93 rolls to the outer peripheral side of the clutch groove 92, the steel ball 93 protruding from the taper portion 91 causes the inner cap surface 98 to be pressed from the rear to move the linkage cap 96 forward. Become. Each contact pin 75 of the spacer ring 70 of the brake mechanism 5B is in contact with the front plate portion 97 of the linkage cap 96.

In the grinder 1A configured as described above, when the switch 9 is OFF, the brake plate 72 is braked by the coil spring 73 and the brake shoe 78 brakes the driven plate 65 of the driven shaft 31 as shown in FIG. It is pressed to the reverse position (brake position) that contacts the surface 65a. At this time, the spacer ring 70 is also retracted at the same time, and the contact pin 75 protrudes rearward of the driven plate 65 to contact the linkage cap 96, thereby pressing the linkage cap 96 rearward. Therefore, in the clutch mechanism 5 </ b> A, each steel ball 93 is pressed by the inner tapered surface 98 and is positioned at the deepest portion 94 of the clutch groove 92.
On the other hand, in the centrifugal clutch 60A, the tension springs 90 bias the clutch claws 85 to the contracted positions (clutch release positions) that are spaced apart from the clutch surface 84a of the outer cylinder portion 84, with the tip ends of the clutch claws 85 being in the inner positions.
Therefore, the driven shaft 31 is braked when the brake shoe 78 of the brake plate 72 is pressed against the braking surface 65a of the driven plate 65, and the spindle 35 where the bevel gears 34 and 36 are engaged is also braked.

When the switch lever 48 is pushed in from here and the switch 9 is turned on, the motor 3 is driven to rotate the output shaft 12 together with the rotor 11. Therefore, the drive shaft 80 integrated with the output shaft 12 also rotates (here, clockwise rotation toward the front). Then, as shown in FIG. 7, each steel ball 93 moves outward on the rolling surface 95 from the deepest portion 94 of the clutch groove 92 due to the centrifugal force generated in the flange 81, via the spacer ring 70 and the linkage cap 96. The linkage cap 96 is moved forward against the urging of the coil spring 73 transmitted. Accordingly, the spacer ring 70 is pushed back against the bias of the coil spring 73 through the contact pin 75, so that the brake plate 72 is also advanced through the bearing 71, and the brake shoe 78 is moved from the driven plate 65. It moves to the front position (brake release position) that separates.
At the same time, in the centrifugal clutch 60A, the distal end side of each clutch pawl 85 swings to the outer position against the urging force of the tension spring 90 by the centrifugal force generated in the flange 81, and the arc plate portion 96 is the clutch of the outer cylinder portion 84. It moves to the expansion position (clutch connection position) that presses the surface 84a.
Therefore, the driven shaft 31 connected to the centrifugal clutch 60A and separated from the brake plate 72 rotates integrally with the drive shaft 80, rotates the spindle 35 via the bevel gears 34, 36, and rotates the disc-shaped grindstone 42.

When the pushing operation of the switch lever 48 is released and the switch 9 is turned off, the energization to the motor 3 is stopped. At this time, the spindle 35 tries to rotate due to inertia, but since the centrifugal force to each steel ball 93 is reduced by stopping the energization, the brake plate 72 and the spacer ring 70 are retracted by the bias of the coil spring 73, and the brake shoe 78. Returns to the retracted position (brake position) in contact with the braking surface 65a of the driven plate 65. By retracting the spacer ring 70, the linkage cap 96 is retracted via the contact pin 75 and each steel ball 93 is returned to the deepest portion 94 of the clutch groove 92.
At the same time, in the centrifugal clutch 60A, the distal end side of each clutch pawl 85 is swung to the inner position by the bias of the tension spring 90 due to the decrease in centrifugal force, and the circular arc plate portion 86 is separated from the clutch surface 84a of the outer cylinder portion 84 in FIG. Return to the contracted position (clutch release position).
As a result, braking is applied to the driven shaft 31 via the driven plate 65, and the braking force is transmitted to the spindle 35 to immediately stop the disc-shaped grindstone 42.

  Here, when energization to the motor 3 is stopped and the output shaft 12 decelerates, the spindle 35 tries to continue to rotate due to inertia. Therefore, the drive shaft 80 that decelerates with the output shaft 12 and inertial rotation with the spindle 35 try to rotate. A speed difference is generated between the driven shaft 31 and a force in the reverse rotation direction is applied to the drive shaft 80 via the linkage cap 96 with which the spacer ring 70 abuts. For this reason, the steel balls 93 positioned outside the spiral clutch grooves 92 are quickly moved inward, and the linkage cap 96 is quickly retracted. Therefore, braking by the backward movement of the spacer ring 70 and the brake plate 72 is also quickly performed.

  Thus, also in the grinder 1A of the above-described form 2, the power is connected between the output shaft 12 and the spindle 35 from the output shaft 12 to the spindle 35 side when the switch 9 is turned on in conjunction with the ON / OFF of the switch 9. The clutch mechanism 5A that cuts off the power from the output shaft 12 to the spindle 35 when the switch 9 is turned off is provided on the spindle 35 side with respect to the clutch mechanism 5A. When the power is cut off by the clutch mechanism 5A, the spindle 35 is By providing the brake mechanism 5B that brakes and releases the brake of the spindle 35 when the power is connected by the clutch mechanism 5A, there is no need to provide an interlocking mechanism between the brake mechanism 5B and the switch lever 48. When the switch 9 is OFF, only the driven shaft 31 on the spindle 35 side where the power is cut off by the clutch mechanism 5A. It is sufficient to multiply the braking by the brake mechanism 5B for. Therefore, the influence of heat generation and the possibility of the obstacle to the cooling flow path of the motor 3 are reduced, and even the large grinder 1A can brake the disc-shaped grindstone 42 easily and reliably.

In particular, here, the clutch mechanism 5A is a centrifugal clutch 60A that connects / disconnects power as the rotational speed of the output shaft 12 increases / decreases. Can be easily performed.
Further, the clutch mechanism 5A is connected to the steel ball 93 that moves in the radial direction in accordance with the increase of the centrifugal force on the output shaft 12 side, and moves in the axial direction in accordance with the movement of the steel ball 93 to link with the brake mechanism 5B. By having the linkage cap 96 for releasing the brake of the spindle 35, the connection of power by the clutch mechanism 5A and the release of the brake of the spindle 35 by the brake mechanism 5B can be executed at appropriate timing.

Further, the centrifugal clutch 60A is disposed on the outer side in the radial direction of the output shaft 12, and the steel ball 93 and the linkage cap 96 are disposed on the inner side of the centrifugal clutch 60A in the radial direction. The timing of interruption and the timing of braking and releasing by the brake mechanism 5B can be set separately.
In addition, the steel ball 93 moves along the clutch groove 92 arranged in a spiral shape around the output shaft 12 so that the steel ball 93 can be moved quickly in response to a change in centrifugal force. The braking by the brake mechanism 5B and the release thereof are quickly performed.

On the other hand, the inner peripheral surface of the outer cylindrical portion 84 that is continuously provided on the radially outer side of the driven plate 65 is connected to the clutch surface 84a where the centrifugal clutch 60A is connected / disconnected, and the continuous side of the outer cylindrical portion 84 in the driven plate 65. Since the opposite surface is a braking surface 65a pressed against the brake plate 72 provided in the brake mechanism 5B, the driven plate 65 is used for connecting the clutch mechanism 5A and the brake mechanism even if the centrifugal clutch 60A that expands and contracts is provided. It can also be used for 5B braking.
Further, the spacer that penetrates the brake mechanism 5B through the driven plate 65 and contacts the linkage cap 96 of the clutch mechanism 5A, and separates the brake plate 72 from the driven plate 65 in accordance with the movement of the linkage cap 96 toward the driven plate 65. Since the ring 70 is provided, braking and release of the driven plate 65 can always be executed at an appropriate timing.

In the second embodiment, the number of steel balls and the shape of the clutch groove can be appropriately changed, and the moving body is not limited to the ball, and a pin shape or the like may be adopted. The centrifugal clutch can also be provided with a shoe on the outer peripheral surface of the arc plate portion or have another shape, as well as the number of clutch pawls being increased or decreased.
In addition, the inner peripheral surface of the outer cylinder portion of the driven plate and the outer peripheral surface of the arc plate portion of the clutch pawl are subjected to surface treatment, or the brake shoe of the brake plate is omitted and the rear surface of the brake plate and / or the front surface of the driven plate is omitted. A surface treatment may be applied.

[Form 3]
In the clutch / brake mechanism 5 of the grinder 1B shown in FIGS. 11 to 13, the drive shaft 100 in the intermediate housing 4 is integrated with the output shaft 12 by press-fitting the rear end into a recess 12 a provided at the front end of the output shaft 12. ing. In the drive shaft 100, a washer 101 is externally provided on the front side of the bearing 16, and a pair of keys 102 and 102 are provided in front of the shaft 16 in a point-symmetrical position, and a sleeve 103 is integrally formed on the front side portion of the key 102. Are combined.
As shown in FIGS. 14 and 15, the clutch mechanism 5 </ b> A here is a steel ball as a coupling body that fits into the recesses 104, 104.. 105, 105,... And a large-diameter portion 106 extending through the rear end of the driven shaft 31 to cover the sleeve 103 and having through holes 107, 107,. The clutch operating plate 108, which is externally moved in the axial direction, has a front and rear thick portion 109 that covers the entire circumference of the through holes 107, 107,. And comprising. The inner peripheral front side of the thick portion 109 is a tapered surface 110 that expands toward the front.

Therefore, when the clutch operating plate 108 is in the forward position where the thick portion 109 closes each through hole 107 over the entire circumference, the radial movement of each steel ball 105 is restricted and the drive shaft 100 and the driven shaft 31 are moved. Becomes a clutch connected state in which the steel balls 105, 105,... Straddling the recess 104 and the through hole 107 are connected.
On the other hand, when the clutch operating plate 108 is in the retracted position where the tapered surface 110 of the thick portion 109 opens each through hole 107, the radial movement of each steel ball 105 is allowed and the engagement with the recess 104 is achieved. By engaging only with the through-hole 107 without being maintained, a clutch disengaged state is established in which the connection between the drive shaft 100 and the driven shaft 31 is released.

  Further, the clutch operation plate 108 has four fan-like switching protrusions 111, 111,... Which are widened toward the outer side in the radial direction on the outer peripheral side of the thick portion 109 at equal intervals in the circumferential direction. Yes. The switching protrusion 111 is formed with a thickness so that the front surface is flush with the front surface of the thick portion 109, and both side surfaces in the circumferential direction are inclined so as to gradually become wider toward the rear. It has become. In addition, a pair of protrusions 113, 113 are provided on the outer circumferential surface of each switching projection 111 in the radial direction, and are provided corresponding to the inner circumferential surface of the inner cylinder 20 of the intermediate housing 4. It is engaged with the axial grooves 114, 114. Therefore, the clutch operation plate 108 can move back and forth while being restricted in rotation within the inner cylinder 20. Further, a rear brake shoe 115 is fixed in a ring shape on the rear surface of the clutch operation plate 108, and a rear coil spring 116 as an urging means is interposed between the outer side of the rear brake shoe 115 and the partition wall 15, The clutch operation plate 108 is urged forward.

Next, the brake mechanism 5B includes a front brake plate 120 and a rear brake plate 121 respectively mounted on the driven shaft 31 and the drive shaft 100 in addition to the clutch operation plate 108 provided with the rear brake shoe 115, and a cam described later. A brake operation plate 122 that is externally attached to the front of the clutch operation plate 108 with the plate 140 interposed therebetween.
First, the front brake plate 120 has a disk shape with four inner protrusions 125, 125,... Fitted in four guide grooves 124, 124,. Between the cap 126 fitted in the front part of the intermediate part 123 and the large diameter part 106, it is provided so that the driven shaft 31 can rotate integrally and back and forth. On the outer periphery of the front brake plate 120, a holding ring 127 as a holding means is provided so that four elastic pieces 128, 128... Protrude toward the center side and the front side. By pressing the front brake plate 120, the front brake plate 120 is elastically held in a retracted position that contacts the front surface of the large-diameter portion 106.

  The rear brake plate 121 is a disk shape having key grooves 129 and 129 in which the keys 102 and 102 of the drive shaft 100 are fitted on the inner periphery, and can rotate integrally with the drive shaft 100 between the washer 101 and the sleeve 103. It is provided so that it can move back and forth. Also on the outer periphery of the rear brake plate 121, a holding ring 130 is fitted as a holding means in which four elastic pieces 131, 131,. By pressing the washer 101, the rear brake plate 121 is elastically held at an advanced position where it abuts against the sleeve 103.

The brake operation plate 122 has a disk shape that is the same diameter as the clutch operation plate 108 and is externally mounted on the large-diameter portion 106. Like the clutch operation plate 108, the brake operation plate 122 has a fan-shaped 4 that becomes wider toward the outside in the radial direction. .. Are provided at equal intervals in the circumferential direction. Both side surfaces of the switching protrusion 132 in the circumferential direction are also guide surfaces 133 and 133 which are inclined so as to gradually become wider as going forward.
Further, a plurality of protruding pieces 134, 134,... Are formed at equal intervals on the outer periphery of the brake operation plate 122, and axial protrusions 135, 135 provided at equal intervals in the circumferential direction on the inner periphery of the cup 23. By engaging between the brake operation plates 122, the brake operation plate 122 can move back and forth while being restricted in rotation. The switching protrusion 111 of the clutch operation plate 108 whose rotation is restricted together and the switching protrusion 132 of the brake operation plate 122 are located in the same phase facing each other.
Further, a ring-shaped front brake shoe 136 is fixed to the front surface of the brake operation plate 122, and as an urging means between the brake operation plate 122 and the folded portion 24 of the cup 23 outside the front brake shoe 136. The front coil spring 137 is interposed to urge the brake operation plate 122 backward.

A disc-shaped cam plate 140 is rotatably mounted on the large diameter portion 106 between the clutch operation plate 108 and the brake operation plate 122. The cam plate 140 has four cam projections 141, 141,... Fitted between the switching projections 111, 111,. , 142.
Further, on the front surface of the cam plate 140, there are four cam recesses 143, 143,... Which are positioned between the cam protrusions 141, 141 in the axial direction and into which the switching protrusions 132, 132,. However, it is similarly formed in the shape which made the both sides | surfaces of the circumferential direction into the inclined surfaces 144,144. A quadrangular engagement protrusion 145 protrudes upward from the upper portion of the cam plate 140 and protrudes upward through a notch 146 provided at the rear end of the cup 23.

On the other hand, on the upper surface of the intermediate housing 4, as shown in FIG. 16, a solenoid 147 as an electric actuator having a main body 148 with a built-in coil 148 a and a plunger 149 that can be retracted from the main body 148 is provided on the plunger 147. It is fixed sideways facing left.
In addition, a pin 150 is erected in the vertical direction on the upper surface of the cup 23 in front of the solenoid 147, and a rotation lever 151 as a connecting member is rotatably supported by the pin 150.
The rotary lever 151 is a band-like member that extends horizontally with a fulcrum portion 152 bent upward in a U-shape, and is rotatably supported by the pin 150, and a force point portion 153 on the distal end side is inclined in an L-shape upward. It is bent and inserted into a slit 154 provided at the tip of the plunger 149 of the solenoid 147. A long hole 155 is formed at the tip of the force point portion 153, and the force pin portion 153 is connected to the plunger 149 by loosely inserting a stop pin 156 provided on the plunger 149 in the slit 154 into the long hole 155. ing.
An angled action point portion 157 is formed on the rear edge of the rotary lever 151 on the side of the force point portion 153 with respect to the fulcrum portion 152.

Here, in the OFF (non-energized) state of the solenoid 147, as shown in FIG. 17A, the plunger 149 is in the protruding position from the main body 148, and the action point portion 157 is the engaging protrusion of the cam plate 140. It is located on the left side of 145. At this time, as shown in FIGS. 12A and 13, the cam plate 140 is pressed by the rear coil spring 116 from the rear side of the clutch operation plate 108 and the front coil spring 137 by the brake operation plate 122 from the front side. The cam projections 141 and 141 of the cam plate 140 are fitted between the switching projections 111 and 111 of the clutch operation plate 108, and the switching projections 132 of the brake operation plate 122 are fitted into the cam recesses 143 of the cam plate 140, respectively. It is in the left rotation position.
Therefore, the clutch operating plate 108 covers the through hole 107 of the large-diameter portion 106 on the rear side of the thick portion 109 to restrict the movement of the steel balls 105, 105... And the rear brake shoe 115 from the rear brake plate 121. It is in a forward movement position (clutch connection position, drive shaft 100 side brake release position) that is separated forward.
In addition, the brake operation plate 122 is configured to move the front brake shoe 136 backward from the front brake plate 120 (the brake release position on the driven shaft 31 side) by fitting the switching protrusions 132 into the cam recesses 143, respectively. It is in.

  On the other hand, when the solenoid 147 is turned on (energized), as shown in FIG. 17B, the plunger 149 is drawn into the main body 148, and the rotation lever 151 is rotated counterclockwise around the pin 150 in plan view. Then, the action point portion 157 presses the engagement protrusion 145 from the left side to rotate the cam plate 140 to the right. By this clockwise rotation, as shown in FIG. 12 (B), the switching protrusion 111 of the clutch operation plate 108 fitted between the cam protrusions 141 and 141 of the cam plate 140 causes the guide surface 112 and the inclined surface 142 to Therefore, the clutch operating plate 108 is retracted to the position where the tapered surface 110 of the thick portion 109 is outside the through hole 107 of the large-diameter portion 106 against the bias of the rear coil spring 116 (see FIG. Move back to the clutch release position. Therefore, each steel ball 105 is allowed to move in the radial direction and is not maintained in the fitted state in the concave portion 104, so that the rotation of the drive shaft 100 is not transmitted to the driven shaft 31.

Further, when the clutch operation plate 108 is retracted, the rear brake shoe 115 comes into contact with the rear brake plate 121 and brakes the drive shaft 100 via the rear brake plate 121 (brake position on the drive shaft 100 side). That is, the clutch operation plate 108 also functions as a second brake operation plate, and the brake mechanism 5B includes a brake mechanism including the brake operation plate 122 and the front brake plate 120, and a first mechanism including the clutch operation plate 108 and the rear brake plate 121. A second brake mechanism.
Furthermore, since each switching protrusion 132 of the brake operation plate 122 fitted in each cam recess 143 of the cam plate 140 is pushed forward by the guide of the inclined surface 144 and the guide surface 133, the brake operation plate 122 is The front brake shoe 136 abuts against the front brake plate 120 against the bias of the front coil spring 137, and moves to a forward position (braking position on the driven shaft 31 side) where the driven shaft 31 is braked via the front brake plate 120. Advance.
The rotary lever 151 includes a pin 150 and an engaging protrusion 145, and a fulcrum part 152 and an action point part 157 are accommodated inside the gear housing 6 so that the force point part 153 protrudes above the upper surface of the intermediate housing 4. ing. An upper cover 158 (FIG. 12) that covers the solenoid 147 and the force point 153 of the rotary lever 151 is screwed to the upper surface of the intermediate housing 4.

In the grinder 1B configured as described above, when the switch 9 is OFF, the solenoid 147 is OFF and the plunger 149 is in the protruding position. Therefore, as described above, since the cam plate 140 is in the left rotation position, the clutch operation plate 108 is in the forward movement position, the clutch of the clutch mechanism 5A is engaged, and the brake to the drive shaft 100 is released. Further, the brake operation plate 122 is in the retracted position and releases the brake to the driven shaft 31.
When the switch lever 48 is pushed in from here and the switch 9 is turned on, the motor 3 is driven to rotate the output shaft 12 together with the rotor 11. Therefore, the drive shaft 100 integrated with the output shaft 12 also rotates (here, clockwise rotation toward the front). Then, the driven shaft 31 connected to the drive shaft 100 via the steel balls 105, 105,... Of the clutch mechanism 5A also rotates together with the drive shaft 100, and the spindle 35 is rotated via the bevel gears 34, 36 to form a disk shape. The grindstone 42 is rotated.

When the pushing operation of the switch lever 48 is released and the switch 9 is turned off, the energization to the motor 3 is stopped. At this time, the solenoid 147 is turned on and the plunger 149 is pulled in after a predetermined time (several seconds) after the switch 9 is turned off by the delay circuit provided in the controller, and the rotating lever 151 is rotated. The reason for waiting for the elapse of a certain time after the switch 9 is turned off is that there is a case where it is desired to perform the operation by pushing the switch lever 48 again after the switch 9 is turned off.
Then, the cam plate 140 rotates clockwise, and in the clutch mechanism 5A, as described above, the clutch operation plate 108 moves backward against the bias of the rear coil spring 116 and the steel balls 105, 105. Therefore, the power transmission from the drive shaft 100 to the driven shaft 31 is interrupted.

At the same time, the rear brake shoe 115 of the clutch operation plate 108 presses the rear brake plate 121, so that the drive shaft 100 and the output shaft 12 are braked via the rear brake plate 121. In addition, the brake operation plate 122 moves forward and the front brake shoe 136 presses the front brake plate 120, so that the driven shaft 31 is braked via the front brake plate 120. At this time, when the front brake plate 120 and the rear brake plate 121 are pressed against the front brake shoe 136 and the rear brake shoe 115, the front brake plate 120 and the rear brake plate 121 are elastically moved by the elastic pieces 128 and 131, so that the impact during braking is small. .
As a result, the disc-shaped grindstone 42 immediately stops via the spindle 35. When a certain time elapses after the switch 9 is turned off, the solenoid 147 is turned off, the cam plate 140 returns to the left rotation position, the clutch operation plate 108 returns to the forward position, and the brake operation plate 122 returns to the reverse position. The controller controls the motor 3 not to be re-driven even if the switch lever 48 is pushed in until the solenoid 147 is turned off after the solenoid 147 is turned on and the brake mechanism 5B is turned on.

  As described above, according to the grinder 1B of the third aspect, between the output shaft 12 and the spindle 35, the switch 9 is linked to ON / OFF, and when the switch 9 is turned ON, power is output from the output shaft 12 to the spindle 35 side. The clutch mechanism 5A is connected and shuts off the power from the output shaft 12 to the spindle 35 side when the switch 9 is turned off. The clutch mechanism 5A is provided closer to the spindle 35 than the clutch mechanism 5A. And a brake mechanism 5B for releasing the brake of the spindle 35 when the power is connected by the clutch mechanism 5A, so that there is no need to provide an interlocking mechanism between the brake mechanism 5B and the switch lever 48. When the switch 9 is OFF, only the driven shaft 31 on the spindle 35 side where the power is cut off by the clutch mechanism 5A is applied. It is sufficient to multiply the braking by the brake mechanism 5B in. Therefore, the influence of heat generation and the possibility of the obstacle to the cooling flow path of the motor 3 are reduced, and even the large grinder 1B can brake the disc-shaped grindstone 42 easily and reliably. Furthermore, since the brake mechanism 5B is released in the initial state where the grinder 1B is not used, the responsiveness to the ON operation of the switch 9 by the switch lever 48 is good, and no time lag occurs in the rotation of the disc-shaped grindstone 42.

In particular, here, a solenoid 147 is provided which is in an OFF state when the switch 9 is ON and is turned ON when the switch 9 is OFF. While the power to the side 35 is cut off, the brake mechanism 5B releases the braking of the spindle 35 when the solenoid 147 is OFF, and brakes the spindle 35 when the solenoid 147 is turned ON. 5A and the brake mechanism 5B can be operated quickly.
Further, a cam plate 140 that rotates in conjunction with ON / OFF of the solenoid 147 is provided, and as the cam plate 140 rotates, a clutch operation plate 108 provided in the clutch mechanism 5A and a brake operation plate provided in the brake mechanism 5B. 122 is moved in the axial direction to operate the clutch mechanism 5 </ b> A and the brake mechanism 5 </ b> B. Therefore, a rational configuration is achieved in which both mechanisms are operated via one cam plate 140.

In the third aspect, the rear brake shoe is provided on the clutch operation plate, the rear brake plate is provided behind the clutch operation plate, and the second brake mechanism is also arranged on the drive shaft (output shaft) side. The second brake mechanism on the side may be omitted and only the configuration in which the clutch operating plate is urged to the cam plate by the rear coil spring may be employed.
Further, the brake plate holding means may use a coil spring or the like externally mounted on the driven shaft, instead of the holding ring having the elastic piece.
Further, in the third aspect, the driven shaft is externally connected to the drive shaft and connected with the steel ball, but conversely, the driven shaft may be externally connected to the driven shaft and connected with a connecting body such as a steel ball. . The connecting body is not limited to a steel ball, and a roller shape that is long in the axial direction can also be adopted.

On the other hand, the solenoid is not limited to the upper side of the housing but may be arranged on the side or the lower side. The connecting member is not limited to the rotary lever, and the center is rotatably connected to the housing side, and one end is the cam plate. The cam plate can be rotated in the direction opposite to the direction in which the plunger protrudes and retracts as a swing lever whose other end is connected to the solenoid plunger.
Further, such a connecting member may be omitted and the cam plate may be directly connected to the plunger.

In common with the first to third embodiments, one or both of the drive shaft on the output shaft side and the driven shaft on the spindle (rotary shaft) side are omitted, and a clutch / brake mechanism is directly provided between the output shaft and the spindle. It may be provided.
It is also conceivable to add an electric brake function to the motor and use it together with the mechanical brakes of Embodiments 1 to 3. In this case, after the switch is turned off, it is desirable to first brake with an electric brake and then brake with a mechanical brake. In the case of this combined type, the structure of the mechanical brake is not limited to those in the first to third embodiments, and other structures can be employed.
In addition, the present invention can be applied even when a battery pack is used as a power source, a brushless motor is used as a motor, or another rotating tool such as a sander.

  1, 1A, 1B ... Grinder, 2 ... Motor housing, 3 ... Motor, 4 ... Intermediate housing, 5 ... Clutch / brake mechanism, 5A ... Clutch mechanism, 5B ... Brake mechanism, 6 ... Gear Housing, 7 ... Output section, 8 ... Handle housing, 9 ... Switch, 12 ... Output shaft, 15 .... Bulk, 20 .... Inner cylinder, 23 ... Cup, 30, 80, 100 ... Drive shaft 31 ··· Drive shaft, 35 · · Spindle, 42 · · Disc-shaped grindstone, 46 · · Handle portion, 55 · · Conversion plate, 57, 81 · · · Flange, 58 · · Clutch shoe, 60, 60A · · Centrifugal Clutch, 61, 92 ... Clutch groove, 62 ... Clutch pin, 63, 94 ... Deepest part, 64, 142, 144 ... Inclined surface, 65 ... Driven plate, 65a ... Braking surface, 65b ... Latch surface, 70 ... spacer ring, 72 ... brake plate, 73 ... coil spring, 75 ... contact pin, 78 ... brake shoe, 82 ... support pin, 84 ... outer cylinder, 84a ... clutch Surface, 85 ... Clutch claw, 90 ... Tension spring, 93, 105 ... Steel ball, 96 ... Link cap, 108 ... Clutch operating plate, 109 ... Thick part, 110 ... Tapered surface, 111, ... 132 .... Switching projection, 112, 133 ... Guide surface, 115 ... Rear brake shoe, 116 ... Rail coil spring, 120 ... Front brake plate, 121 ... Rear brake plate, 122 ... Brake operating plate, 127 , 130.. Retaining ring 128, 131, elastic piece, 136, front brake shoe, 137, front coil spring, 140, cam plate, 141, cam projection, 143, Cam recess 145 ... engaging projection, 147 ... solenoid, 149 ... plunger, 151 ... rotating lever, 152 ... supporting point portion, 153 ... point portion, 157 ... action point portion.

Claims (11)

A motor, a switch that controls the rotation of the output shaft of the motor by performing an ON / OFF operation in accordance with the operation of the operation member, and a rotation shaft that rotates in accordance with the rotation of the output shaft and rotates the tip tool. A rotating tool comprising:
Between the output shaft and the rotating shaft,
A clutch mechanism that interlocks with ON / OFF of the switch, connects power from the output shaft to the rotating shaft when the switch is ON, and shuts off power from the output shaft to the rotating shaft when the switch is OFF When,
A brake mechanism that is provided closer to the rotary shaft than the clutch mechanism and brakes the rotary shaft when power is cut off by the clutch mechanism, and releases brake of the rotary shaft when power is connected by the clutch mechanism. When,
A rotary tool characterized in that is provided.   The rotary tool according to claim 1, wherein the clutch mechanism is a centrifugal clutch that connects / disconnects power as the rotational speed of the output shaft increases / decreases.   The centrifugal clutch includes a conversion member that makes contact with and separates from the driven plate provided on the rotating shaft side in the axial direction as the rotational speed increases and decreases and presses the driven plate to connect power. The rotary tool according to claim 2.   The rotary tool according to claim 3, wherein a surface of the driven plate opposite to the pressing side of the conversion member is a braking surface pressed by a brake member provided in the brake mechanism.   The clutch mechanism includes a moving body that moves in a radial direction in response to an increase in centrifugal force on the output shaft side, an axial direction that moves in accordance with the movement of the moving body, and is linked to the brake mechanism. The rotary tool according to claim 2, further comprising a linkage member that releases braking of the rotary tool.   The rotation according to claim 5, wherein the centrifugal clutch is disposed outside in the radial direction of the output shaft, and the movable body and the linkage member are disposed inside the centrifugal clutch in the radial direction. tool.   The rotary tool according to claim 5 or 6, wherein the movable body moves along a groove arranged in a spiral shape around the output shaft.   A driven plate is provided on the rotating shaft side, and an inner peripheral surface of an outer cylindrical portion connected to a radially outer side of the driven plate is a clutch surface on which the centrifugal clutch is connected / disconnected, and the driven plate has the The rotary tool according to claim 6 or 7, wherein a surface of the outer cylinder portion opposite to the continuous side is a braking surface pressed by a brake member provided in the brake mechanism.   The brake mechanism penetrates the driven plate and contacts the conversion member or the linking member of the clutch mechanism, and from the driven plate to the brake plate according to the movement of the conversion member or the linking member to the driven plate side. The electric tool according to claim 4, wherein a spacer member for separating the brake member is provided.   There is provided a solenoid that is OFF when the switch is ON and that is ON when the switch is OFF, and the clutch mechanism connects power to the rotary shaft side when the solenoid is OFF, and the rotary shaft when the solenoid is ON The power to the side is cut off, and the brake mechanism releases the braking of the rotating shaft when the solenoid is OFF, and brakes the rotating shaft when the solenoid is turned ON. The described rotary tool.   A cam plate that rotates in conjunction with ON / OFF of the solenoid is provided. Along with the rotation of the cam plate, a clutch operation plate provided in the clutch mechanism and a brake operation plate provided in the brake mechanism are axially arranged. The rotary tool according to claim 10, wherein the clutch mechanism and the brake mechanism are operated by moving the clutch mechanism.

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